Charge-coupled devices (CCD) and complementary metal-oxide semiconductor (CMOS) devices are common types of optical sensing components adopted for applications such as digital cameras, digital camcorders, fax machines, scanners, spectrometers, etc. For fax machines, scanners and spectrometers, linear optical sensing components are usually employed. In order to enhance the efficiency of a linear CCD or CMOS sensing device, it is typical in current technology to dispose a plano-convex cylindrical lens on the sensing device, as shown in FIG. 1. The total amount of light received by the linear sensing device 1 is thus increased by the unilateral optical convergence provided by the plano-convex cylindrical lens 2, thereby improving the sensitivity and the optical reception of the sensing device. The plano-convex cylindrical lens has a flat surface for the ease of being mechanically assembled with the linear optical sensing component. Nevertheless, there exists certain difficulties in design and manufacture of plano-convex cylindrical lenses, which contribute to a higher overall cost.
As progresses are constantly made in various micro-machining and micro-manufacturing technologies, such as ones used in semiconductor processes, the miniaturization of optical apparatuses is also developing rapidly. In particular, various components of a miniaturized spectrometer may be integrated onto a single chip by replacing, to name a few, flat mirrors, planar optical gratings and converging lenses of a conventional spectrometer with concave gratings manufactured by technologies such as semiconductor processes, micro-electro-mechanical systems (MEMS) or Lithographie GaVanoformung Abformung (LIGA). Moreover, when the spectrometer with concave gratings is further furnished with a planar optical waveguide, the amount of light received at an optical sensing component of the spectrometer can be increased. Consequently, the spectrometer can have its size greatly reduced, making it more convenient to use and suitable for a wider range of applications. In contrast, a plano-convex cylindrical lens that is assembled with the optical sensing component of a conventional spectrometer is generally fabricated by methods of mechanical machining, and is thus limited in its minimal size and maximal surface curvature. This would result in difficulties for such a lens to be applied to or employed by a miniaturized spectrometer or other miniaturized optical apparatuses.
Therefore, for applications such as miniaturized spectrometers and other integrated optical apparatuses and systems, it is critical to provide a solution whereby the sensitivity and optical reception efficiency of optical sensing components can be enhanced by increasing the total amount of light received by the optical sensing components.